Pneumatic tire



june 13 19240 C. E. BONNER PNEUMATIC TIRE Filed July 5, 19225 Patented June 3, 192% T oFFic CLABENCE E. BONNEIL OF NEW YORK, N. Y., ASSIGNOR TO RENNOBEC COMPANY, OF

DOVER, DELAWARE, A. CORPORATION OF PNEUMATIC TIRE.

To all whom it may concern:

Be it known that I, CLARENCE E. BONNER, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements inPneumatic Tires, of which the following is a specification.

This invention relates to a new and improved pneumatic tire and more particularly to a pneumatic tire assembly adapted to automatically close up punctures. and to prevent escape of air from the tube. It is well known in the art that inner tubes can be rendered self-healing by being formed with a thickened tread portion and being reversed when strip ed from the mandrel so that the inner portlon of the tread is held under compression by the tensile strength of the outer portion of the tread. However,

it has been found in practice that it is necessaryto provide some means for increasing the tensile strength of the outer portionin order to provide adequate compression of the inner portion of the tread.

Various means have been devised for providing this increased tensile strength as, for example, imbedding a layer of fabric in the tread. This method, however, is open to objection in that. the tube is subject to rupture at the edge of the fabric. A 'further'difiiculty lies in the fact that the fabriobeing substantially non-stretchable it is necessary to make it of exactly the same length as the inner circumference of the casingwith which it is to be associated. Otherwise there is a tendency for the tube to twist in the casing. It is an object of the present invention to prbvide a new and improved tire assembly wherein adequate compression is afforded'in the tread portion of the inner tube without the reinforcement of the tube itself by any incorporated foreign tensile means.

" It is a further object to provide a construction of this character in whichthe in-' ner tube may be readily adapted for use with standard outer casings without alteration therein.

. It is an additional object to provide a construction utilizin an inner tube which may be readily forme at small cost and which is adapted to adjust itself to variations in the 1923. Serial No. 649,405.

form and contour of the outer casing with which it may be associated.

Other and further objects will appear as the description proceeds.

I have illustrated a preferred embodiment of my invention in the accompanying drawings, in which Figure 1 is a cross section of a casing with a deflated inner tube therein;

Figure 2 is a section showing the tube inflated Figure 3 is a perspective illustrating the .method of forming the tube; and

Figure, 4; is a cross section of the inner tube showing its normal position when deflated.

As shown in Figure 3, the tube 11 is formed upon the mandrel 12 and is provided with the thickened tread portion 13. The tube is stripped from the mandrel by reversing it upon itself as shown in Figure 3 so that the outer surface is put under tension and the inner surface under compression. The two ends of the. tube are then joined in the usual manner.

Thegreater thickness of the tread 13 and its resistance to compression will cause the finished tube to assume the shape shown in cross section in Figure .4 when deflated. If

this tube be used in the casing in the usual manner, when pierced by a puncturing element, there will be a tendency for the compressed inner portion of the tread to close tightly about the entering element and to close again to close up the opening when the element is withdrawn. However, if the tube be not provided with reinforcing means associated with the tread'surface, there is also the tendency for thematerial to tear due to the puncturing rupture and due to the tensile stress set up in the outer surface layers of the tube by the compression of the inner layers.

I counteract this latter tendency b Y securing the tread portion 13 of the tu e to the inner surface of the tread portion 14 of the casing 15 by means of an adhesive 16. This adhesive is brushed into the tread of the casing before the tube is placed therein and, when the inner tube is inflated, it is intimately pressed against the adhesive. This adhesive is of such strength as to effectively prevent relative movement between the two surfaces which it joins. Consequently, when the tube is punctured the tensile strength of the outer portion of the .tube is reinforced by the strength of the casing itself prevents loss ofthe ressure in t e tu This adhesive is, owever, preferably of such a nature as to permit the tube to be manually stripped from the casing when it is desired to remove the tube for inspection or repair. It will be readily apparent that if a relatively weak adhesive is used, it may be entirely adequate to prevent relative movement of the tube and easing parallel to the two contacting surfaces and yet permit the surfaces to be torn apart without injury to either surface.

In this form of tire assembly an inner tube is used entirely without reinforcing material and which can be made rapidly at relatively small cost. The tube may be used in existing types of casing without alteration therein. It may be readily and quickly applied and installed in the casings and when so installed provides a self-healing construction.

I claim:

1. A pneumatic tire assembly comprising an outer casing, an inner tube in said casweenie an outer casing, an inner tube in said casing, and an adhesive of relatively small strength securing the tread portions of said casing and tube together.

3., A pneumatic tire assembly comprising an outer casing, an inner tube in said casing, the inner tube having a thickened tread portion, and an adhesive securin said tube tread portion to the innen surface of the casing tread, said adhesive being of sutlicient strength to prevent relative movementbetweencasing and tube, but permitting the'tube to be manually stripped from the casin Without injury to tube or casing.

4. pneumatic tire assembly comprising an outer casing, an inner tube in said casing, the inner tube having a thickened tread portion, an inner portion of said tread being maintained under compression by an outer portion thereof, and an adhesive seg, curing said tube tread portion to the innei surface of the casing tread, said adhesive being of sutiicient strength to prevent relative movement between casing and tube, out permitting the tube to be manually stripped from the casing without injury to tube or casing. Si

ed at New York, New York, this 6th ay of June, 1923.

CLARENCE E. BONNER. 

